1. Field of the Invention
The present invention relates to a screw hone assembly adapted for use in the honing of a gear manufactured by the gear cutting by forming process, the gear cutting by generating process or other like process.
The purpose of the gear honing is to improve the smoothness or flatness and dimensional accuracy of the tooth surface of the gear, following the shape thereof.
2. Description of the Prior Art
As shown in FIG. 7, the prior art screw type hone 1 includes a hone body 2 comprising a resilient material such as a mixture of urethane rubber and epoxy resin and white alundum grains (hereinafter referred to as the WA grains) mixed therein. As such a polymeric material has insufficient bending or tensile strength, however, there is a fear that the threaded portion may break upon receipt of impacts caused by, e.g., collision or concentrated load. Especially in the case of a screw type hone having a smaller module, the dedendum of the threaded portion is apt to break.
In order to obviate these problems and improve the honing function of the prior art screw type hone 1, it has been proposed to use cubic system boron nitride grains (the CBN grains) in the hone body 2, said grains having a greater harness and exhibiting the most satisfactory honing property with respect to steel materials in comparison with the WA grains. However, such proposal has a disadvantage that the hone body 2 wears out in an earlier stage thanks to the extremely excellent durability of the CBN grains, resulting in earlier escape thereof. Thus, the CBN grains have not effectively been used in the prior art.
Accordingly, the present invention contemplates providing longer service life by using a grain binder formed of a material other than resilient materials such as urethane rubber and epoxy resin, thereby giving rigidity to the overall threaded portion.